Automatic descaling system

ABSTRACT

An automated descaling system can be integrated into a tankless water heater or can be a separate system that is attached to a tankless water heater. The automatic descaling system comprises a cleaning media chamber and a four way valve with a motor. The descaling system can be set on an automatic cleaning schedule.

TECHNICAL FIELD

The present disclosure relates generally to water heaters, and moreparticularly to systems, methods, devices, and valves for automaticallydescaling a water heater.

BACKGROUND

Water heaters are generally used to provide a supply of hot water. Waterheaters can be used in a number of different residential, commercial,and industrial applications. A water heater can supply hot water to anumber of different processes. For example, a hot water heater in aresidential dwelling can be used for an automatic clothes washer, anautomatic dishwasher, one or more showers, and one or more sink faucets.Water heaters generally input water from a municipal source or from awell. Both of these water sources can include calcium and magnesiumcarbonates. Water with higher levels of these minerals is considered“hard water.” The presence of these minerals in water leads toaccumulation of mineral scale deposits (“scaling”) of the water heaterand downstream appliances.

An industry wide problem is the fouling of water heaters due to thesemineral scale deposits, especially on heat transfer surfaces of waterheaters which leads to efficiency losses and possible failure of thewater heater. To mitigate fouling it is recommended that a typicaltankless water heater be cleaned once a year.

SUMMARY

In general, in one aspect, the disclosure relates to a water heatercomprising: a water inlet; a water outlet; a heating chamber; a cleaningmedia chamber fluidly connected to the water outlet and the water inlet;a four way valve comprising a first valve connection, a second valveconnection, a third valve connection, and a fourth valve connection,wherein the first valve connection is connected to the water outlet, thesecond valve connection is configured to be connected to a hot waterpipe, the third valve connection is connected to the cleaning mediachamber; and the fourth valve connection is configured to be connectedto a drain; a motor connected to the four way valve; and, a controllercomprising processing circuitry, wherein the controller is configured tocontrol the motor thereby controlling a path of water through the fourway valve. In some embodiments the water inlet is a cold water inlet anda check valve is installed between the cold water inlet and the cleaningmedia tank. In another embodiment, the water inlet is a return line tothe water heater. In some embodiments, the cleaning media chamber is apod or a cartridge. The cleaning media chamber can comprise a chemicaldescaling agent or an abrasive cleaning agent. The controller can befurther configured to automatically descale the water heater at apredetermined time. In some embodiments, the controller is configured tocalculate a time to descale based on hardness of water and automaticallystart a descaling process once the time to descale has passed. In someembodiments, the water heater additionally comprises a solenoid valve inthe water inlet. The controller can be further configured to operate thesolenoid valve. In embodiments, the controller is further configured toinitiate a cleaning cycle, wherein the cleaning cycle comprises, inorder: rotating the four way valve with the motor such that the four wayvalve forms a fluid path only between the water outlet and the cleaningmedia chamber, thereby allowing flow of water through the cleaning mediachamber and into the water inlet; rotating the four way valve with themotor such that the four way valve forms a fluid path only between thewater outlet and the drain; and rotating the four way valve with themotor such that the four way valve forms a fluid path only between thewater outlet and the hot water pipe. In specific embodiments, the fourway valve is disposed within the water heater.

Another general embodiment of the disclosure is an automatic descalingassembly comprising: a hot water inlet fitting connected to a hot waterinlet line; a hot water outlet fitting connected to a hot water outletline; a drain line fitting connected to a drain line; a water heaterinlet fitting connected to a cleaning media outlet line; a four wayvalve comprising one valve inlet and three valve outlets, wherein thevalve inlet is only fluidly connected to one valve outlet of the threevalve outlets at a time and wherein the valve inlet is connected to thehot water inlet line and the valve outlets are connected to the hotwater outlet line, the drain line, and the cleaning media outlet line; amotor connected to the four way valve; a cleaning media chamber fluidlyconnected to the cleaning media outlet line; and a controller comprisingprocessing circuitry, wherein the controller is configured to controlthe motor thereby controlling a path of water through the four wayvalve. The cleaning media chamber can comprise a chemical descalingagent or an abrasive cleaning agent. In embodiments, the controller isconfigured to calculate a time to descale based on hardness of water. Inspecific embodiments, the controller is further configured to initiate acleaning cycle, wherein the cleaning cycle comprises, in order: rotatingthe four way valve with the motor such that the four way valve forms afluid path only between the hot water inlet line and the cleaning mediaoutlet line, thereby allowing flow of water through the cleaning mediachamber and out of the water heater inlet fitting; rotating the four wayvalve with the motor such that the four way valve forms a fluid pathonly between the hot water inlet line and the drain line; and rotatingthe four way valve with the motor such that the four way valve forms afluid path only between the hot water inlet line and the hot wateroutlet line. The automatic descaling assembly can be configured toattach to a tankless water heater.

A third embodiment of the disclosure is a valve assembly comprising: a)a diverter comprising a drive; and a cylinder comprising an innerthrough hole extending fully through a diameter of the cylinder, a notchconnected to an end of the inner through hole and extending 110-150degrees around a circumference of the cylinder, an inner cleaning holeextending from the bottom of the cylinder and fluidly connected to theinner through hole; and an inner drain hole set apart from the innercleaning hole and extending from the bottom of the cylinder and fluidlyconnected to the inner through hole; b) a housing comprising an innerchamber configured to house at least a portion of the cylinder andallowing rotation of the cylinder about an axis of the cylinder; anouter inlet hole and an outer outlet hole located on opposite sides ofthe housing such that the outer inlet hole and the outer outlet hole arefluidly connected through the inner through hole when the inner throughhole is aligned with the outer inlet hole and the outer outlet hole; anouter cleaning hole extending through the bottom of the housing suchthat the outer cleaning hole can be aligned with the inner cleaning holewhen the inner through hole is not aligned with the outer outlet hole,and when thus aligned, the outer cleaning hole is fluidly connected withthe outer inlet hole through the inner through hole and the notch; andan outer drain hole extending through the bottom of the housing suchthat the outer drain hole can be aligned with the inner drain hole whenthe inner through hole is not aligned with the outer outlet hole andwhen the outer cleaning hole is not aligned with the inner cleaninghole, and when thus aligned, the outer drain hole is fluidly connectedwith the outer inlet hole through the inner through hole and the notch;and c) a motor, wherein the motor is configured to rotate the drive andthereby the cylinder of the diverter. In some embodiments the motor is astep motor. The valve can further comprise o-rings.

These and other aspects, objects, features, and embodiments will beapparent from the following description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate only example embodiments and are therefore notto be considered limiting in scope, as the example embodiments may admitto other equally effective embodiments. The elements and features shownin the drawings are not necessarily to scale, emphasis instead beingplaced upon clearly illustrating the principles of the exampleembodiments. Additionally, certain dimensions or positions may beexaggerated to help visually convey such principles. In the drawings,reference numerals designate like or corresponding, but not necessarilyidentical, elements.

FIG. 1 illustrates an example tankless water heater with an integrateddescaling system.

FIG. 2 illustrates an example standalone descaling system for a tanklesswater heater.

FIGS. 3a-c illustrate the operation of the descaling system at differenttimes in the cleaning cycle. FIG. 3a shows normal operation of atankless water heater. FIG. 3b shows the water heater during a descalingprocess. FIG. 3c shows the water heater during a purge of the waterheater.

FIG. 4 is an example of a four way valve.

FIG. 5 is the inner cylinder of the four way valve of FIG. 4.

FIG. 6 is another view of the inner cylinder of FIG. 5.

FIG. 7 is a block diagram illustrating an example controller for adescaling system.

FIG. 8 is an example flow chart for operation of a descaling system.

DETAILED DESCRIPTION

In general, example embodiments provide systems, methods, devices andvalves for automatic descaling systems for water heaters. The descalingsystems can be standalone systems that are attached to a water heater inuse or the descaling systems can be integrated into a water heater.Further, example embodiments can be located in any type of environment(e.g., warehouse, attic, garage, storage, mechanical room, basement) forany type (e.g., commercial, residential, industrial) of user. Waterheaters used with example embodiments can be used for one or more of anynumber of processes (e.g., automatic clothes washers, automaticdishwashers, showers, sink faucets, heating systems, humidifiers).Example types of water heaters that the automatic descaling system couldbe installed in or with are heating appliances, pool heating equipment,space heating boilers, or other hard to reach heat exchanger systemsotherwise compromised by fouling effects.

Automatic descaling systems for water heaters (or components thereof,including controllers) described herein can be made of one or more of anumber of suitable materials to allow that device and/or otherassociated components of a system to meet certain standards and/orregulations while also maintaining durability in light of the one ormore conditions under which the devices and/or other associatedcomponents of the system can be exposed. Examples of such materials caninclude, but are not limited to, aluminum, stainless steel, copper,fiberglass, glass, plastic, PVC, ceramic, and rubber.

Components of automatic descaling systems for water heaters (or portionsthereof) described herein can be made from a single piece (as from amold, injection mold, die cast, or extrusion process). In addition, orin the alternative, automatic descaling systems for water heaters (orportions thereof) can be made from multiple pieces that are mechanicallycoupled to each other. In such a case, the multiple pieces can bemechanically coupled to each other using one or more of a number ofcoupling methods, including but not limited to epoxy, welding,soldering, fastening devices, compression fittings, mating threads, andslotted fittings. One or more pieces that are mechanically coupled toeach other can be coupled to each other in one or more of a number ofways, including but not limited to fixedly, hingedly, removeably,slidably, and threadably.

In the foregoing figures showing example embodiments of automaticdescaling systems for water heaters, one or more of the components shownmay be omitted, repeated, and/or substituted. Accordingly, exampleembodiments of automatic descaling systems for water heaters should notbe considered limited to the specific arrangements of components shownin any of the figures. For example, features shown in one or morefigures or described with respect to one embodiment can be applied toanother embodiment associated with a different figure or description.Further, the automatic descaling systems for water heaters may be asystem separate from a water heater. For example, the automaticdescaling system may be sold as a standalone system and then installedin an already functioning water heater system. The automatic descalingsystem may also be integrated into a tankless water heater.

In addition, if a component of a figure is described but not expresslyshown or labeled in that figure, the label used for a correspondingcomponent in another figure can be inferred to that component.Conversely, if a component in a figure is labeled but not described, thedescription for such component can be substantially the same as thedescription for a corresponding component in another figure. Further, astatement that a particular embodiment (e.g., as shown in a figureherein) does not have a particular feature or component does not mean,unless expressly stated, that such embodiment is not capable of havingsuch feature or component. For example, for purposes of present orfuture claims herein, a feature or component that is described as notbeing included in an example embodiment shown in one or more particulardrawings is capable of being included in one or more claims thatcorrespond to such one or more particular drawings herein.

In some cases, example embodiments can be subject to meeting certainstandards and/or requirements. Examples of entities that set and/ormaintain standards include, but are not limited to, the Department ofEnergy (DOE), the National Electric Code (NEC), the National ElectricalManufacturers Association (NEMA), the International ElectrotechnicalCommission (IEC), the American Society of Mechanical Engineers (ASME),the National Fire Protection Association (NFPA), the American Society ofHeating, Refrigeration and Air Conditioning Engineers (ASHRAE),Underwriters' Laboratories (UL), and the Institute of Electrical andElectronics Engineers (IEEE). Use of example embodiments describedherein can meet (and/or allow a corresponding water heater system orportion thereof to meet) such standards when required.

Example embodiments of automatic descaling systems for water heaterswill be described more fully hereinafter with reference to theaccompanying drawings, in which example embodiments of a descalingsystem for a water heater are shown. Water heaters with automaticdescaling systems may, however, be embodied in many different forms andshould not be construed as limited to the example embodiments set forthherein. Rather, these example embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of water heaters with hard water determination to those ofordinary skill in the art. Like, but not necessarily the same, elements(also sometimes called components) in the various figures are denoted bylike reference numerals for consistency.

Terms such as “first”, “second”, “third”, “top”, “bottom”, “side”, and“within” are used merely to distinguish one component (or part of acomponent or state of a component) from another. Such terms are notmeant to denote a preference or a particular orientation, and are notmeant to limit embodiments of automatic descaling systems for waterheaters. In the following detailed description of the exampleembodiments, numerous specific details are set forth in order to providea more thorough understanding of the invention. However, it will beapparent to one of ordinary skill in the art that the invention may bepracticed without these specific details. In other instances, well-knownfeatures have not been described in detail to avoid unnecessarilycomplicating the description.

“Connection,” as used herein, refers to directly connected or connectedthrough another component. “Fluidly connected,” as used herein, refersto components that are directly connected or connected through anothercomponent and can also move a fluid between them without leaking. Forexample, a valve and a pump can be fluidly connected through a pipe. Ifa valve is located between two fluidly connected components, thecomponents are still considered fluidly connected as long a fluid pathis possible. “Fitting,” as used herein, refers to a component thatfastens to one or more pipes or tubing sections. “Lines” as use hereinrefers to a water tight tube such as a pipe.

FIG. 1 illustrates an example tankless water heater 100 with anintegrated automatic descaling system. The tankless water heater 100includes a water inlet fitting 102 connected to a water inlet line 104which typically receives unheated water from a municipal water source ora well. Water flows into the water inlet line 104 and then into the heatexchanger 106 which uses a power source, such as electricity or gas(shown), to generate heat which is then exchanged with the water,thereby heating the water. The heat in the heat exchanger 106 can begenerated through electricity or gas. The heated water flows into thefour way valve assembly 114 from a hot water line 115. The heated watercan then flow out of the tankless water heater 100 through a wateroutlet line 108 and an outlet fitting 110 which can be connected to hotwater pipes. The operation of the tankless water heater 100 and thedescaling system is controlled by a controller 112. The integrateddescaling system comprises the four way valve assembly 114 and a mediacompartment 117. The media compartment 117 is connected to a cleaningmedia inlet line 136 and a cleaning media outlet line 137. The tanklesswater heater 100 may also comprise valves 116 that are used in thenormal operation of a tankless water heater. The tankless water heater100 also comprises a return fitting 118, a return line 120, and a returnpump 122, configured to cycle hot water through the plumbing system inorder to keep hot water accessible for instant demand. The four wayvalve assembly 114 is also connected to a drain line 124 and a drainfitting 126 which is configured to be connected to a drain pipe.

Also included in the tankless water heater 100 are an ignitor 128 (alsosometimes called a burner 128), an air moving device 130, and a vent132. The ignitor 128 of the tankless water heater 100 can be a flame orother source of heat that is ignited or otherwise initiated (i.e.electrical) when a demand for heated water is detected. Fuel (e.g.,natural gas, propane) can be delivered to the ignitor 128 through avalve 116 using a gas inlet line 134. The gas inlet line is connected toa gas fitting 140. A hard water sensor 142 may also be included.

The tankless water heater 100 can include multiple signal and/or powertransfer links (not shown). The signal and/or power transfer links canalso be used to transfer signals and/or power between the tankless waterheater 100 components. For example, between the controller 112 and fourway valve assembly 114; between the controller 112 and any one of thevalves 116; between the controller 112 and the air moving device 130;and between the controller 112 and the igniter 128. Signal transferlinks can be wired or wireless.

A signal can be sent from the controller 112 to the four way valveassembly 114 in order to control the direction of water output from thefour way valve 114. The input to the four way valve assembly 114 is fromthe hot water line 115. However, depending on the rotation of the fourway valve assembly 114, the output of the four way valve assembly 114 isto the hot water outlet line 108, the drain line 124, or the cleaningmedia inlet line 136.

The air moving device 130 can be used to direct the heat generated bythe ignitor 128 toward the heat exchanger 106. The air moving device 130can be a fan, a blower, and/or any other device that can force the heatgenerated by the ignitor 128 toward the heat exchanger 106. The airmoving device 130 can be controlled automatically or by the controller112.

A heat exchanger coil 138 is filled with water that is circulatedtherethrough. One end of the coil 138 is coupled to the water inlet line104, thereby receiving unheated water. As the water circulates throughthe coil 138 it continues to absorb the heat absorbed from the ignitor128 by the coil 138. The water in the coil 138 can be circulated using apump, gravity, pressure differentials, and/or any other method forcirculating water. When the water reaches the other end of the coil 138of the heat exchanger 106, the water has absorbed enough heat to becomeheated water. The other end of the coil 138 of the heat exchanger 106 iscoupled to the hot water line 115, the four way valve assembly 114,which is also connected to the hot water outlet line 108, and candeliver the heated water to a pipe connected to the outlet fitting 110.

Those of ordinary skill in the art will appreciate that a tankless waterheater can have any of a number of other configurations. In any case,the controller 112 can be aware of the devices, components, ratings,positioning, and any other relevant information regarding the tanklesswater heater 100. In some cases, one or more devices of the tanklesswater heater 100 can have its own local controller, for example, thefour way valve assembly 114. In such a case, the controller 112 cancommunicate with the local controller using additional signal transferlinks. The tankless water heater 100 can also include a number of othercomponents generally considered part of the appliance system which arenot shown for conciseness.

FIG. 2 is an example of a standalone descaling system 200 for waterheaters. The standalone descaling system 200 comprises a four way valveassembly 202, a cleaning media compartment 204, and a controller 206. Apump 208 may optionally be included. The standalone descaling system ishoused in a descaling assembly housing 210 which includes four fittingsfor pipes to be attached: a hot water inlet fitting 212 configured to beconnected to a hot water outlet from a water heater; a hot water outletfitting 214 configured to be attached to hot water pipes; a drainfitting 216 configured to be connected to a drain; and a water heaterinlet fitting 218 configured to be connected to the return line or waterinlet into a hot water heater. The line from the water heater inletfitting 218 can be connected to the return line or water inlet throughthe use of a check valve, for example. If a pump is already installedwith a return line, the pump 208 may not be needed in the system. Thehot water inlet fitting 212 is connected to the hot water inlet line 220which is also connected to the inlet of the four way valve assembly 202;the hot water outlet fitting 214 is connected to the hot water outletline 222 which is also connected to an outlet of the four way valveassembly 202; and, the drain fitting 216 is connected to the drain line224 which is also connected to an outlet of the four way valve assembly202. An outlet of the four way valve assembly 202 is also connected to acleaning media inlet line 226 which is then connected to the pump 208and the cleaning media compartment 204. The cleaning media compartment204 is connected to a cleaning media outlet line 228 and then to thewater heater inlet fitting 218. In this way, water pumped through thehot water inlet line 220, through the four way valve assembly 202 intothe cleaning media inlet line 226, and into the cleaning mediacompartment 204 where cleaning media gets mixed into the water. Watermixed with the cleaning media is then pumped through the cleaning mediaoutlet line 228, and will then be pumped back into the water heaterthrough a return line or a water inlet line. The inlet of the four wayvalve assembly 202 can only be fluidly connected to one of the threeoutlets of the four way valve assembly 202 at a time. The controller 206is connected to a motor (not shown) on the four way valve assembly 202through a signal transfer link 230. The pump 208 can also be connectedto the controller 206 through a signal transfer link 230. Directions offlow are shown by arrows 326.

FIGS. 3a-c illustrate the operation of an example automatic descalingsystem integrated within a water heater which has a return line 302, areturn line pump (not shown), a water inlet line 304, a solenoid valve306, and a controller 308 installed. The automatic descaling systemincludes a four way valve assembly 310, an inlet line 312, a hot wateroutlet line 314, a drain line 316, a cleaning media inlet line 318, acleaning media outlet line 319, and a cleaning media compartment 320. Acheck valve 322 can be installed between the cleaning media outlet line319 and the return line 302. The solenoid valve 306 is installed in thewater inlet line 304 and controls the flow of water into the waterheater from the water inlet line. A pump (not shown) is installed in thereturn line. When the return line pump is activated water flows from thehot water lines in the building back through the water heater, keepingall of the water within the hot water pipes hot. The controller 308 isconnected to the four way valve assembly 310 and the solenoid valve 306through signal transfer links 324. Direction of the flow of water 326 isshown with dotted arrows in FIGS. 3a-3c

FIG. 3a illustrates the normal operation of the tankless water heaterduring active heating of water. The solenoid valve is open and waterflows through the water inlet line 304 usually from a municipal sourceor from a well and into the heat exchanger (see FIG. 1). When the returnpump is active, water also flows through the return line 302 and intothe heat exchanger. After being heated by the heat exchanger, the waterflows into the inlet line 312, through the four way valve assembly 310and into the hot water outlet line 314. The four way valve assembly 310is configured to flow water from the inlet line 312 and either into thehot water outlet line 314, the drain line 316, or the cleaning mediainlet line 318. The four way valve assembly is configured such that nofluid is exchanged within the four way valve assembly 310 between thehot water outlet line 314, the drain line 316, or the cleaning mediainlet line 318.

When the controller 308 determines that a descaling process should beinitiated, the controller 308 sends a signal to the motor on the fourway valve assembly 310, which rotates the four way valve assembly 310such that fluid only moves from the water inlet line 312 to the cleaningmedia inlet line 318. The controller also closes the solenoid valve 306so that no new water can flow into the system.

FIG. 3b illustrates the first step in the cleaning process when the fourway valve assembly 310 moves fluid from the water inlet line 312 to thecleaning media inlet line 318. In this step, the solenoid valve 306 isclosed as discussed above, so no water is let into the water heater fromthe municipal source. Instead, the return line pump is activated andwater already within the water heater is circulated by the pump throughthe return line 302, into the heat exchanger, through the water inletline 312, through the four way valve assembly 310, into the cleaningmedia inlet line 318, through the cleaning media compartment 320, intothe cleaning media outlet line 319, and back into the return line 302.While the water is being circulated through the lines, the water passesthrough the cleaning media compartment 310 and cleaning media isdissolved or suspended in the water. The cleaning media is thencirculated with the water through the tankless water heater, therebydescaling the lines within the tankless water heater. Additionally, thepump can be paused during the descaling cycle in order to let thecleaning media soak within the water heater.

When the controller 308 determines that enough time has passed, orenough cycles of circulation through the cleaning media chamber haspassed, the controller 308 sends a signal to the motor on the four wayvalve assembly 310, which rotates the four way valve assembly 310 suchthat the fluid only moves from the water inlet line 312 to the drainline 316 as shown in FIG. 3c . The controller 308 also opens thesolenoid valve 306, allowing new water into the water heater. Water thenenters the tankless water heater through the water inlet line, washingthrough the coils, and back through the water inlet line 312 and out thedrain line 316, thus, flushing the cleaning solution out of the tanklesswater heater, without letting any of the cleaning solution back into thehot water supply to be used by a user.

The configurations shown in FIGS. 3b and 3c can be cycled back and forthas determined by the controller 308. After the last purging of thecleaning material (FIG. 3c ), the tankless water heater can resumenormal operation, as shown in FIG. 3 a.

Cleaning media is located inside of the cleaning media compartment 320.The media compartment can be intrinsic to the descaling system or thecleaning compartment can be added to the descaling system. For example,the media compartment can be a cartridge or a pod that slots into thedescaling system or water heater. In some embodiments, the mediacompartment is a disposable media container. In another embodiment, themedia compartment is a refillable cartridge. The refillable cartridgecould be mailed to a distributer and recycled. In some embodiments, themedia container is a disposable container, such as a pod, in which atube can perforate the container to access the media. The mediacompartment can also be individually identifiable, for example by acartridge encoding mechanism. In some embodiments, the cartridgeencoding mechanism could be RFID, EEPROM, magnetic strip, and/or barcodes, for example.

The cleaning media can be any type of media used to descale an appliancesuch as a chemical cleaning media or an abrasive cleaning media.Examples of chemical cleaning media are acetic acid, hydrochloric acid,and citric acid.

Any four way valve assembly can be used within the disclosure thatallows one inlet to be fluidly connected to one of three outlets at atime. FIGS. 4-6 disclose one example of a four way valve assembly thatcan be used within an automatic descaling system.

FIG. 4 is an exterior view of a four way valve assembly 400. Therotating four way valve assembly comprises a motor 402, a housing 404,and a cylinder internal to the housing 404 (see FIGS. 5 and 6). Thehousing 404 comprises an outer inlet hole 406, and outer outlet hole408, an outer cleaning hole 410, and an outer drain hole 412. Thehousing also comprises an inner cylindrical chamber configured to housethe cylinder.

FIG. 5 shows the internal view of the valve 400 comprising drive 500 andcylinder 502. The drive 500 is attached to the cylinder 502. The drive500 slots into the motor 402, and when the motor 402 turns the drive500, the cylinder 502 also turns. The cylinder 502 sits within an innercylindrical chamber of the housing 404. An inner through hole 504 runsthrough a diameter of the cylinder 502 and can be aligned with the outerinlet hole 406 and the outer outlet hole 408. A notch 506 is connectedto one end of the inner through hole 504 and extends about 130 degreesaround the circumference of the cylinder 502. As the cylinder 502 isrotated clockwise, out of alignment with the outer inlet hole 406 andthe outer outlet hole 408, the outer inlet hole 406 is still fluidlyconnected to the inner through hole 406 by the notch 506 for about 120degrees of rotation, while the outer outlet hole 408 is not fluidlyconnected to the inner through hole 406. An inner drain hole 508 extendsfrom the bottom of the cylinder 502 (opposite the motor 402) and isfluidly connected to the inner through hole 504. An inner cleaning hole510 is set apart from the inner drain hole 508 and extends from thebottom of the cylinder 502 (opposite the motor 402) and is fluidlyconnected to the inner through hole 504 (FIG. 6).

When the inner through hole 504 is aligned with the outer inlet hole 406and the outer outlet hole 408, water can only move through the rotatingvalve assembly 400 through the outer inlet hole 406, through the innerthrough hole 504 and out of the outer outlet hole 408 (alignment definedherein as 0°).

When the cylinder is rotated by the motor 60° from 0°, the outer outlethole 408 is moved out of alignment with the inner through hole 408 andis cut off from the flow of water. However, the outer inlet hole 406 isstill fluidly connected with the inner through hole 504 through thenotch 506. At 60° rotation, the inner cleaning hole 510 aligns with theouter cleaning hole 410, while the inner drain hole 508 is not alignedwith the the outer drain hole 412. Thus, at 60° water can only movethrough the rotating valve assembly 400 through the outer inlet hole406, through the notch 506, through the inner through hole 504, throughthe inner cleaning hole 510, and out the outer cleaning hole 410.

When the cylinder is rotated by the motor 120° from 0°, the outer outlethole 408 is out of alignment with the inner through hole 408 and is cutoff from the flow of water. However, the outer inlet hole 406 is stillfluidly connected with the inner through hole through the notch 506. At120° rotation, the inner drain hole 508 aligns with the outer drain hole412, while the inner cleaning hole 510 is not aligned with the outercleaning hole 410. Thus, at 120°, water can only move through therotating valve assembly 400 through the outer inlet hole 406, throughthe notch 506, through the inner through hole 504, through the innerdrain hole 508, and out the outer drain hole 412.

The motor 402 can be any type of motor that is able to rotate the innercylinder into the proper position to connect the inlet to the properoutlet. In some embodiments the motor is a step motor or a servomotors.The servomotor could include an encoder or AC/DC motor with limitswitches. O-rings are located throughout the rotating four way valveassembly 400, as needed to isolate fluid pathways and prevent leakage.

If the descaling system is integrated into a water heater, the waterheater controller can function to also control the descaling system. Ifthe descaling system is a standalone descaling system, the standalonesystem may also include a controller. In embodiments, the standalonedescaling system comprises a controller that is configured to interfacewith the controller of a water heater. FIG. 7 below illustrates anembodiment of a controller that is integrated into a water heater. Manyof the parts and functions illustrated within the controller 700 of FIG.7 can also be used within the controller of a standalone system. Itshould be understood that a standalone system controller would notnecessarily need all of the components described in FIG. 7 below thatfunction to control the operation of the water heater during normaloperation. As such, there are components of the controller 700 shown inFIG. 7 that may be left out of a controller on a standalone descalingsystem.

FIG. 7 is an example embodiment of a controller 700 that is integratedinto a tankless water heater and can include one or more of a number ofcomponents. Such components, can include, but are not limited to, acontrol engine 702, a communication module 704, a timer 706, an energymetering module 708, a power module 710, a storage repository 712, ahardware processor 714, a memory 716, a transceiver 718, and anapplication interface 720. FIG. 7 also illustrates example connectionsof the controller 700 to one or more input/output (I/O) devices 724,user 726, sensors 742, valves 744, and a power supply 722. A bus (notshown) can allow the various components and devices to communicate withone another. A bus can be one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. A bus can include wired and/orwireless buses. The components shown in FIG. 7 are not exhaustive, andin some embodiments, one or more of the components shown in FIG. 7 maynot be included in an example system. Further, one or more componentsshown in FIG. 7 can be rearranged. Any component of the examplecontroller can be incorporated into a tankless water heater and can bediscrete or combined with one or more other components of a tanklesswater heater.

A user 726 may be any person or entity that interacts with an automaticdescaling system, a tankless water heater and/or the controller 700.Examples of a user 726 may include, but are not limited to, an engineer,an appliance or process that uses heated water, an electrician, aninstrumentation and controls technician, a mechanic, an operator, aconsultant, a contractor, a homeowner, a landlord, a building managementcompany, and a manufacturer's representative. There can be one ormultiple users 726.

The user 726 can use a user system (not shown), which may include adisplay (e.g., a GUI). The user 726 can interact with (e.g., sends datato, receives data from) the controller 700 via the application interface720 (described below). The user 726 can also interact with a tanklesswater heater (including any components thereof, such as one or more ofthe sensor devices) and/or the power supply 722. Interaction between theuser 726, the controller 700, the tankless water heater, the four wayvalve assembly 736, and the power supply 722 can be conducted usingsignal transfer links 734.

Each signal transfer link 734 can include wired (e.g., Class 1electrical cables, Class 2 electrical cables, electrical connectors,electrical conductors, electrical traces on a circuit board, power linecarrier, DALI, RS485) and/or wireless (e.g., Wi-Fi, visible lightcommunication, cellular networking, Bluetooth, WirelessHART, ISA100)technology. For example, a signal transfer link 734 can be (or include)one or more electrical conductors that are coupled to the controller 700and to the four way valve assembly 736. A signal transfer link 734 cantransmit signals (e.g., communication signals, control signals, data)between the controller 700, the user 726, the tankless water heater(including components thereof), and/or the power supply 722.

The power supply 722 provides power to one or more components (e.g., thethe four way valve assembly 736, the controller 700, the heat exchanger)of a tankless water heater. The power supply 722 can include one or moreof a number of single or multiple discrete components (e.g., transistor,diode, resistor), and/or a microprocessor. The power supply 722 mayinclude a printed circuit board, upon which the microprocessor and/orone or more discrete components are positioned.

The power supply 722 can include one or more components (e.g., atransformer, a diode bridge, an inverter, a converter) that receivespower (for example, through an electrical cable) from an independentpower source external to the heating system 100 and generates power of atype (e.g., AC, DC) and level (e.g., 12V, 24V, 120V) that can be used byone or more components of the tankless water heater and/or automaticdescaling system. In addition, or in the alternative, the power supply722 can be a source of power in itself. For example, the power supply722 can be a battery, a localized photovoltaic power system, or someother source of independent power.

The user 726, the power supply 722, and/or the four way valve assembly736, can interact with the controller 700 using the applicationinterface 720 in accordance with one or more example embodiments.Specifically, the application interface 720 of the controller 700receives data (e.g., information, communications, instructions, updatesto firmware) from and sends data (e.g., information, communications,instructions) to the user 726, the power supply 722, and/or othercomponents of a tankless water heater. The user 726, the power supply722, and other components of a tankless water heater can include aninterface to receive data from and send data to the controller 700 incertain example embodiments. Examples of such an interface can include,but are not limited to, a graphical user interface, a touchscreen, anapplication programming interface, a keyboard, a monitor, a mouse, a webservice, a data protocol adapter, some other hardware and/or software,or any suitable combination thereof.

The controller 700, the user 726, the power supply 722, and/or othercomponents of a tankless water heater can use their own system or sharea system in certain example embodiments. Such a system can be, orcontain a form of, an Internet-based or an intranet-based computersystem that is capable of communicating with various software. Acomputer system includes any type of computing device and/orcommunication device, including but not limited to the controller 700.Examples of such a system can include, but are not limited to, a desktopcomputer with LAN, WAN, Internet or intranet access, a laptop computerwith LAN, WAN, Internet or intranet access, a smart phone, a server, aserver farm, an android device (or equivalent), a tablet, smartphones,and a personal digital assistant (PDA). Further, as discussed above,such a system can have corresponding software (e.g., user software,sensor device software). The software of one system can be a part of, oroperate separately but in conjunction with, the software of anothersystem within a tankless water heater.

The storage repository 712 can be a persistent storage device (or set ofdevices) that stores software and data used to assist the controller 700in communicating with the user 726, the power supply 722, and othercomponents of the tankless water heater and/or automatic descalingsystem. In one or more example embodiments, the storage repository 712stores one or more protocols 728, algorithms 730, and stored data 732.The protocols 728 can be any procedures (e.g., a series of method steps)and/or other similar operational procedures that the control engine 702of the controller 700 follows based on certain conditions at a point intime. The protocols 728 can include any of a number of communicationprotocols 728 that are used to send and/or receive data between thecontroller 700 and the user 726, the power supply 722, and the waterheater 190. A protocol 728 can be used for wired and/or wirelesscommunication. Examples of a protocol 728 can include, but are notlimited to, Modbus, profibus, Ethernet, and fiberoptic.

The algorithms 730 can be any formulas, logic steps, mathematicalmodels, and/or other suitable means of manipulating and/or processingdata. One or more algorithms 730 can be used for a particular protocol728. As discussed above, the controller 700 uses information provided bysensors 742 or input to generate, using one or more protocols 728 and/orone or more algorithms 730, information related to the descaling of thetankless water heater.

For example, a protocol 728 and/or an algorithm 730 can dictate when adescaling cycle is to be entered, how many cycles to run, and when tore-enter normal operation. Such protocols 728 and algorithms 730 can bebased on information received from sensors 742, from data entered from auser 726, or may be static variables that are programed into thecontroller 700.

Stored data 732 can be any data associated with a tankless water heater(including any components thereof), any measurements taken by sensors742, time measured by the timer 706, adjustments to an algorithm 730,threshold values, user preferences, default values, results ofpreviously run or calculated algorithms 730, water system variables suchas the harness of water in the system and/or any other suitable data.Such data can be any type of data, including but not limited tohistorical data for the water heater, calculations, adjustments made tocalculations based on actual data, and measurements taken by one or moresensor devices. The stored data 732 can be associated with somemeasurement of time derived, for example, from the timer 706.

Examples of a storage repository 712 can include, but are not limitedto, a database (or a number of databases), a file system, a hard drive,flash memory, some other form of solid state data storage, or anysuitable combination thereof. The storage repository 712 can be locatedon multiple physical machines, each storing all or a portion of theprotocols 728, the algorithms 730, and/or the stored data 732 accordingto some example embodiments. Each storage unit or device can bephysically located in the same or in a different geographic location.

The storage repository 712 can be operatively connected to the controlengine 702. In one or more example embodiments, the control engine 702includes functionality to communicate with the user 726, the powersupply 722, and other components of the tankless water heater and/orautomatic descaling system. More specifically, the control engine 702sends information to and/or receives information from the storagerepository 712 in order to communicate with the user 726, the powersupply 722, and other components. As discussed below, the storagerepository 712 can also be operatively connected to the communicationmodule 704 in certain example embodiments.

In certain example embodiments, the control engine 702 of the controller700 controls the operation of one or more components (e.g., thecommunication module 704, the timer 706, the transceiver 718) of thecontroller 700. For example, the control engine 702 can activate thecommunication module 704 when the communication module 704 is needed tosend data received from another component (e.g., the four way valveassembly 736).

As another example, the control engine 702 can acquire the current timeusing the timer 706. The timer 706 can enable the controller 700 tocontrol the components within a tankless water heater. As yet anotherexample, the control engine 702 can direct a sensor 742, such as pHsensor, flow sensor, or temperature sensor, to measure a parameter(e.g., conductivity, temperature, flow rate, pH) and send themeasurement by reply to the control engine 702. In some cases, thecontrol engine 702 of the controller 700 can control the position (e.g.,open, closed, fully open, fully closed, 50% open) of valves within thetankless water heater. In some embodiment, the controller 700 cancontrol the operation of a descaling operation within the tankless waterheater.

The control engine 702 can be configured to perform a number offunctions that help the control engine 702 make a determination (anestimate) that relates to the time between automatic descalingoperations. For example, the control engine 702 can execute any of theprotocols 728 and/or algorithms 730 stored in the storage repository 712and use the results of those protocols 728 and/or algorithms 730 tocommunicate to a user 726. FIG. 8 below provides more specific examplesof how the control engine 702 functions according to certain exampleembodiments. The control engine 702 can generate an alert or some otherform of communication when an automatic descaling operation is initiatedand/or ended. In some embodiments, when the controller 700 determinesthat a descaling operation should be initiated, the controller 700additionally determines if the descaling operation should be initialedinstantly, or if the controller should wait an additional amount oftime. For example, the controller 700 could wait to run the descalingoperation at a more convenient time, such as during the night or attimes determined to have low usage of the water heater.

Using one or more algorithms 730, the control engine 702 can predict theexpected time before the tankless water heater 100 needs to be descaledbased on sensor data, stored data 732, a protocol 728, one or morethreshold values, and/or some other factor. The control engine 702 cankeep track of the time between descaling operations and initiate anautomatic descaling operation when such a time is reached. Thecontroller 700 can also monitor sensor data during the descalingoperation to determine when all of the cleaning media has been used andto restore normal operation at such a time. For example, if a chemicalmedia is used for descaling a pH sensor can be used to determine whenall of the chemical media has been purged from the system and only cleanwater is being cycled through the system. Using one or more algorithms730, the control engine 702 can also predict the number of cleaningcycles (active cleaning, FIG. 3b and purging, FIG. 3c ) needed based onthe hardness of water in the system. One embodiment of determining ifextra cleaning cycles are needed would utilize a TDS/hardness sensor andlook at the TDS or conductivity of the cleaning agent—as scale isremoved the TDS or conductivity would increase. The algorithm then runscleaning cycles until a threshold TDS ceases to be reached. Anotherexample method would be to employ empirical data based on supply waterhardness and time between cleanings.

The control engine 702 can perform its evaluation functions andresulting actions on a continuous basis, periodically, during certaintime intervals, or randomly. Further, the control engine 702 can performthis evaluation for the present time or for a period of time in thefuture. For example, during the first startup of a tankless waterheater, the control engine 702 can use sensor 742 data to determine anadjusted conductivity, such as the total dissolved solids in a volume ofwater, based on sensor data and output the determination to a user. Thecontrol engine 702 can also prompt a user 726 to enter the hardness ofwater in the system to be used to predict the time to descaling.

In certain embodiments, the control engine 702 of the controller 700 cancommunicate with one or more components (e.g., a network manager) of asystem external to the tankless water heater 100. For example, thecontrol engine 702 can interact with an inventory management system byordering a component (e.g., cleaning media) to use to descale thetankless water heater that the control engine 702 has determined needsto be descaled.

The power module 710 of the controller 700 provides power to one or moreother components (e.g., timer 706, control engine 702) of the controller700. In addition, in certain example embodiments, the power module 710can provide power to one or more components (e.g., the heat exchanger104) of the tankless water heater 100.

The energy metering module 708 of the controller 700 measures one ormore components of power (e.g., current, voltage, resistance, VARs,watts) at one or more points (e.g., output of the power supply 722)associated with a water heater. The energy metering module 708 caninclude any of a number of measuring devices and related devices,including but not limited to a voltmeter, an ammeter, a power meter, anohmmeter, a current transformer, a potential transformer, and electricalwiring.

The power module 710 can include one or more components (e.g., atransformer, a diode bridge, an inverter, a converter) that receivespower (for example, through an electrical cable) from the power supply722 and generates power of a type (e.g., AC, DC) and level (e.g., 12V,24V, 120V) that can be used by the other components of the controller700 and/or by the water heater.

In addition, or in the alternative, the power module 710 can be a sourceof power in itself to provide signals to the other components of thecontroller 700. For example, the power module 710 can be a battery. Asanother example, the power module 710 can be a localized photovoltaicpower system. In certain example embodiments, the power module 710 ofthe controller 700 can also provide power and/or control signals,directly or indirectly, to the four way assembly 736, sensors 742, andvalves 744, for example. In such a case, the control engine 702 candirect the power generated by the power module 710 to one or more of thedevices. In this way, power can be conserved by sending power to thedevices when those devices need power, as determined by the controlengine 702.

The hardware processor 714 of the controller 700 executes software,algorithms 730, and firmware in accordance with one or more exampleembodiments. Specifically, the hardware processor 714 can executesoftware on the control engine 702 or any other portion of thecontroller 700, as well as software used by the user 726, the powersupply 722, and the water heater (or portions thereof). The hardwareprocessor 714 can be an integrated circuit, a central processing unit, amulti-core processing chip, SoC, a multi-chip module including multiplemulti-core processing chips, or other hardware processor in one or moreexample embodiments. The hardware processor 714 is known by other names,including but not limited to a computer processor, a microprocessor, anda multi-core processor.

In one or more example embodiments, the hardware processor 714 executessoftware instructions stored in memory 716. The memory 716 includes oneor more cache memories, main memory, and/or any other suitable type ofmemory. The memory 716 can include volatile and/or non-volatile memory.The memory 716 is discretely located within the controller 700 relativeto the hardware processor 714 according to some example embodiments. Incertain configurations, the memory 716 can be integrated with thehardware processor 714.

In certain example embodiments, the controller 700 does not include ahardware processor 714. In such a case, the controller 700 can include,as an example, one or more field programmable gate arrays (FPGA), one ormore insulated-gate bipolar transistors (IGBTs), and one or moreintegrated circuits (ICs). Using FPGAs, IGBTs, ICs, and/or other similardevices known in the art allows the controller 700 (or portions thereof)to be programmable and function according to certain logic rules andthresholds without the use of a hardware processor. Alternatively,FPGAs, IGBTs, ICs, and/or similar devices can be used in conjunctionwith one or more hardware processors 714.

The transceiver 718 of the controller 700 can send and/or receivecontrol and/or communication signals. Specifically, the transceiver 718can be used to transfer data between the controller 700 and the user726, the power supply 722, and a tankless water heater (or portionsthereof). The transceiver 718 can use wired and/or wireless technology.

Memory 716 represents one or more computer storage media. Memory 716includes volatile media (such as random access memory (RAM)) and/ornonvolatile media (such as read only memory (ROM), flash memory, opticaldisks, magnetic disks, and so forth). Memory 716 includes fixed media(e.g., RAM, ROM, a fixed hard drive, etc.) as well as removable media(e.g., a flash memory drive, a removable hard drive, an optical disk,and so forth).

One or more I/O devices 724 allow a customer, utility, or other user toenter commands and information to a tankless water heater, and alsoallow information to be presented to the customer, utility, or otheruser and/or other components or devices. Examples of input devicesinclude, but are not limited to, a keyboard, a cursor control device(e.g., a mouse), a microphone, a touchscreen, and a scanner. Examples ofoutput devices include, but are not limited to, a display device (e.g.,a display, a monitor, or projector), speakers, outputs to a lightingnetwork (e.g., DMX card), a printer, and a network card.

Various techniques are described herein in the general context ofsoftware or program modules. Generally, software includes routines,programs, objects, components, data structures, and so forth thatperform particular tasks or implement particular abstract data types. Animplementation of these modules and techniques are stored on ortransmitted across some form of computer readable media. Computerreadable media is any available non-transitory medium or non-transitorymedia that is accessible by a computing device. By way of example, andnot limitation, computer readable media includes “computer storagemedia.”

FIG. 8 shows a flowchart for an example embodiment. While the varioussteps in the flowchart are presented and described sequentially, one ofordinary skill in the art will appreciate that some or all of the stepscan be executed in different orders, combined or omitted, and some orall of the steps can be executed in parallel depending upon the exampleembodiment. Further, in one or more of the example embodiments, one ormore of the steps described below can be omitted, repeated, and/orperformed in a different order. In addition, a person of ordinary skillin the art will appreciate that additional steps not shown in FIG. 8 canbe included in performing these methods in certain example embodiments.

Accordingly, the specific arrangement of steps should not be construedas limiting the scope. In addition, a particular computing device, asdescribed, for example, in FIG. 7 above, is used to perform one or moreof the steps for the methods described below in certain exampleembodiments. For the methods described below, unless specifically statedotherwise, a description of the controller 700 performing certainfunctions can be applied to the control engine 702 of the controller700.

An example method of FIG. 8 begins at the START step. The START could beduring the installation and set-up of a water heater, for example. Instep 802 a time to descale variable is set which determines the amountof time that should pass before a descaling process is initiated. Thetime to descale variable can be set to a specific date, or can be anamount of time that needs to pass, for example, a predetermined amountof time. The time to descale (predetermined time) can be a set timeperiod, such as 1 year, 11 months, 10 months, or 9 months, for example.The time to descale can be calculated based on other variables, such asthe hardness of water that will pass through the water heater. Once theamount of time to descaling has passed, or the date and time ofdescaling occurs, a descaling process is initiated (step 806). The fourway valve assembly is positioned such that hot water output from the hotwater heater is diverted through a cleaning media compartment whichmixes cleaning media into the water and cycles the cleaning media backthrough the water heater (step 810). In step 810 inlet valves connectingthe water heater to new water are closed. The cleaning media water canbe constantly cycled back through the water heater for a set period oftime and/or the water cycling can be paused such that the water heatersoaks with the cleaning media water. In step 812 the cleaning mediawater is purged from the water heater. In this step the four way valveassembly is positioned such that hot water output from the hot waterheater is diverted to the drain line, while valves allowing clean waterare open such that clean water enters the water heater from the inletline. Step 812 can occur for a predetermined amount of time or the waterheater can monitor a variable, such as pH, to determine when all of thecleaning media water has been purged from the water heater. In step 814,if the controller determines that another cycle should be run, theprocess returns to step 810. The number cleaning cycles can be a setamount of cycles, such as 0, 1, 2, 3, 4, 5, 6, or 7, or the controllercan calculate the number of cycles needed. If another cycle is notentered, the controller returns the water heater to normal operation andstarts the clock again.

The automatic descaling system cleans and protects a tankless waterheating unit in an automated fashion, thereby reducing the effort on theconsumer's part, ensuring optimum performance, and offering whole systemprotection. By monitoring and routinely cleaning the unit, the automaticdescaling system protects the appliance while keeping consumer requiredmaintenance and attention to a minimum, as well as reducing overallmaintenance cost. The system can permit routine cleaning to take placewithout the need for professional services offered by plumbers.

Although embodiments described herein are made with reference to exampleembodiments, it should be appreciated by those skilled in the art thatvarious modifications are well within the scope of this disclosure.Those skilled in the art will appreciate that the example embodimentsdescribed herein are not limited to any specifically discussedapplication and that the embodiments described herein are illustrativeand not restrictive. From the description of the example embodiments,equivalents of the elements shown therein will suggest themselves tothose skilled in the art, and ways of constructing other embodimentsusing the present disclosure will suggest themselves to practitioners ofthe art. Therefore, the scope of the example embodiments is not limitedherein.

What is claimed is:
 1. A water heater comprising: a water inlet; a wateroutlet; a heating chamber; a cleaning media chamber fluidly connected tothe water outlet and the water inlet; a four way valve comprising afirst valve connection, a second valve connection, a third valveconnection, and a fourth valve connection, wherein the first valveconnection is connected to the water outlet, the second valve connectionis configured to be connected to a hot water pipe, the third valveconnection is connected to the cleaning media chamber; and the fourthvalve connection is configured to be connected to a drain; a motorconnected to the four way valve; and, a controller comprising processingcircuitry, wherein the controller is configured to: determine whether toinitiate a descaling process; and in response to determining to initiatethe descaling process, (i) output a signal to a pump to direct a flow ofwater to the water inlet, and (ii) output a signal to the motor of thefour way valve to direct the flow of water to the cleaning media chambersuch that a mixture of at least a portion of the flow of water and atleast a portion of cleaning media contained within the cleaning mediachamber is directed from the cleaning media chamber to the water inlet.2. The water heater of claim 1, wherein the water inlet is a cold waterinlet and a check valve is installed between the cold water inlet andthe cleaning media chamber.
 3. The water heater of claim 1, wherein thewater inlet is a return line, the return line being configured to directwater from the water heater.
 4. The water heater of claim 1, wherein thecleaning media chamber is a pod or a cartridge.
 5. The water heater ofclaim 1, wherein the cleaning media chamber comprises a chemicaldescaling agent.
 6. The water heater of claim 1, wherein the cleaningmedia chamber comprises an abrasive cleaning agent.
 7. The water heaterof claim 1, wherein the controller is further configured toautomatically initiate the descaling process at a predetermined time. 8.The water heater of claim 1, wherein the controller is configured tocalculate a time to descale based on hardness of water and automaticallyinitiate the descaling process once the time to descale has passed. 9.The water heater of claim 1, wherein the water heater additionallycomprises a solenoid valve in the water inlet.
 10. The water heater ofclaim 9, wherein the controller is further configured to operate thesolenoid valve.
 11. The water heater of claim 1, wherein the controlleris further configured to: initiate the descaling process, wherein thedescaling process comprises, in order: rotating the four way valve withthe motor such that the four way valve forms a fluid path only betweenthe water outlet and the cleaning media chamber, thereby allowing flowof water through the cleaning media chamber and into the water inlet;rotating the four way valve with the motor such that the four way valveforms a fluid path only between the water outlet and the drain; androtating the four way valve with the motor such that the four way valveforms a fluid path only between the water outlet and the hot water pipe.12. The water heater of claim 1, wherein the four way valve is disposedwithin the water heater.